Sorter Detects and Removes Damaged Popcorn
Kernels

A device developed by an Agricultural Research Service (ARS)
scientist to sort wheat has been successfully used to detect and remove popcorn
kernels that have been damaged by fungi.

ARS engineer
Tom
Pearson in Manhattan, Kan., developed the low-cost, high-speed device to
inspect and separate a variety of grains based on color variations or slight
defects. This technology was previously applied to sorting white and red wheat
grains.

The system achieved 74 percent accuracy when removing popcorn with
fungal damage called blue-eye, and was 91 percent accurate at recognizing
undamaged popcorn, according to Pearson, at the ARS
Center
for Grain and Animal Health Research in Manhattan. The sorter, which uses a
specially-designed camera linked to a processor, can handle 88 pounds of
popcorn per hour. Pearson is currently designing a sorting machine that has
much higher accuracy and can handle greater volumes.

Blue-eye damage in corn is characterized by a small blue spot of the
popcorn germ and is caused by certain species of Aspergillus and
Penicillin, which can grow under poor storage conditions and can affect
up to 20 percent of the popcorn harvest. Blue-eye can be minimized if popcorn
is dried before storage to reduce its internal moisture to no more than 14
percent.

The sorting device combines a color image sensor with what's called a
field-programmable gate array, which is a programmable, electrical circuit that
Pearson configured to execute image processing in real-time, without the need
for an external computer.

The sorter also could be useful for detecting and removing other
defective grains, such as insect-damaged grain, scab-damaged wheat, and bunted
wheat. Parts for the system cost less than $2,000, suggesting that it may be
economical to simultaneously operate several of the systems to keep up with
processing plant rates.

ARS is the principal intramural scientific research agency in the
U.S. Department of
Agriculture (USDA). This research supports the USDA priorities of promoting
international food security and ensuring food safety.